I think personal tests to one's own requirements are always the best - part of getting to know your camera. Just to add, the same goes for you raw processing tools.

The subthread below seems to confirm that. It seems that the ISO on the NEX 5N (and maybe other Sony cameras?) just is a tag in the RAW file. No gain/amplification or digital scaling/multiplication at all. Seems that DxO missed that!

The Sony raw coding is unusual, because they use a non-linear 12 bit code (at least in some cameras) - I think we'd want to look closely to convince ourselves that the non-linearity remains the same from ISO to ISO.

The 'spikes' in (especially) the shadows (to the left) get wider as the ISO increases, but maybe that has something to do with long exposure NR? (suppose that "2, f/2.8" means 2 seconds, f/2.8)

I wouldn't expect NR to change the histogram on that scale, it would mean hugely visible smudging if that was true. Think, the nature of NR is to change pixels to very nearly the same tone, but within the same distribution of tomes that already exist. If it goes inventing new tones, the results will look very strange indeed.

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Bob

We have many unanswered questions here, but I find it very interesting that the NEX 5N RAW files seem to be able to 'handle' the same exposure without clipping at all (or at least most) ISOs. Seems to me that DxO's Measured ISO therefore also should be the same at all (or most) ISOs.

PS - That should make it possible to shoot 'ISO-less' with the 5N, and still get JPEGs with the 'correct' brightness. Or rather, it'll give you the advantage of 'ISO-less' shooting (more headroom), without actually shooting 'ISO-less'.